Configuring communications for a load control system

ABSTRACT

A load control system may include multiple control devices that may send load control messages to load control devices for controlling an amount of power provided electrical loads. To prevent collision of the load control messages, the load control messages may be transmitted using different wireless communication channels. Each wireless communication channel may be assigned to a load control group that may include control devices and load control devices capable of communicating with one another on the assigned channel. A control device may send load control messages to a load control device within a transmission frame allocated for transmitting load control messages. The transmission frame may include equal sub-frames and load control messages may be sent at a random time within each sub-frame. Control devices may detect a status event within a sampling interval to offset transmissions from multiple control devices based on detection of the same event.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/833,643, filed on Jun. 11, 2013, entitled CONFIGURINGCOMMUNICATIONS FOR A LOAD CONTROL SYSTEM, the disclosure of which ishereby incorporated by reference herein in its entirety.

BACKGROUND

FIG. 1 depicts an example prior art load control environment 102, suchas a room in a residence or an office building. As shown in FIG. 1, theload control environment 102 may include various types of load controldevices for controlling an electrical load. The load control devices mayinclude a lighting control device 104 (e.g., a dimmer switch, a ballast,or a light-emitting diode (LED) driver) for directly controlling anamount of power provided from an alternating-current (AC) to anelectrical load, such as a lighting load 106, a motorized windowtreatment 112 for controlling the position of a covering material 114, athermostat 120 for controlling an HVAC system, and/or a plug-in loadcontrol device 122 for controlling an amount of power provided to afloor lamp 124, a table lamp, an appliance, or an electrical load ofanother device that is plugged in to the plug-in load control device122. The lighting control device 104, the motorized window treatment112, the thermostat 120, and/or the plug-in load control device 122 maybe two-way communication devices. The lighting control device 104, themotorized window treatment 112, the thermostat 120, and/or the plug-inload control device 122 may be control-target devices that may becapable of receiving and/or implementing control instructions based onload control messages received from one or more control-source devices.

The load control environment 102 may include one or more control-sourcedevices that may transmit load control messages to the control-targetdevices. The control-source devices may be one-way communicationdevices. The control-source devices may include a daylight sensor 108,an occupancy sensor 110, a shadow sensor 116 (e.g., a window sensor or acloudy-day sensor), and/or a remote control device 118. The remotecontrol device 118 may include a wireless switch, a wireless dimmer, ahandheld remote control, a keypad, a cellular phone, a tablet, oranother wireless remote control device capable of sending a load controlmessage to a control-target device. The load control message from theremote control device 118 may include a user identified command forcontrolling a control-target device. The daylight sensor 108 may send aload control message to a control-target device based on a detectedlevel of available daylight in the load control environment 102. Theoccupancy sensor 110 may send a load control message to a control-targetdevice based on detected movement or lack of movement within the loadcontrol environment 102. The shadow sensor 116 may send a load controlmessage to a control-target device based on a measured level of lightreceived from outside of the load control environment 102. For example,the shadow sensor 116 may detect when direct sunlight is directlyshining into the shadow sensor, is reflected onto the shadow sensor, oris blocked by external means, such as clouds or a building, and may senda message indicating the measured light level. The shadow sensor 116 maybe installed at a window level to communicate current exterior lightconditions.

A control-target device may control a corresponding electrical loadbased on the information included within the load control messagesreceived from one or more control-source devices. The lighting controldevice 104 may increase or decrease the lighting level of the lightingload 106 based on the information received within a load controlmessage. The thermostat 120 may increase or decrease the temperature ofthe load control environment 102 based on the information receivedwithin a load control message. The motorized window treatment 112 mayraise or lower the position of the covering material 114 based on theinformation received within a load control message. The plug-in loadcontrol device 122 may turn on and off and/or increase or decrease thepower provided to the floor lamp 124, or other device that may beplugged in to the plug-in load control device 122, based on theinformation received within a load control message.

The control-source device may send the load control message to thecontrol-target device directly or via a system controller 126. Thecommunications between the control-source device and the control-targetdevice may be wireless or wired communications. The load control messagemay include load control instructions or an indication of a status eventfrom which load control instructions may be determined. The systemcontroller 126 may receive the indication of the status event and maydetermine load control instructions for being sent to one or morecontrol-target devices. The status event may include a user identifiedcommand (e.g., increase or decrease a dimming level of the lighting load106), a measured light level in the load control environment 102, adetected movement or lack of movement within the load controlenvironment 102, an amount of light directly received from outside ofthe load control environment 102, or another status event that may beused to control an electrical load.

FIG. 2A depicts an example prior art environment in which multiple loadcontrol messages may be transmitted within a wireless range 204. Asshown in FIG. 2A, the wireless range 204 may include one or more loadcontrol environments 102 a, 102 b, 102 c. The load control environments102 a, 102 b, 102 c may be included in a building 202. Load controlenvironments 102 a and 102 b may be on separate floors in the building202. Load control environments 102 a and 102 c may be on the same floorin the building 202. Each load control environment 102 a, 102 b, 102 cmay include one or more load control devices, such as a lighting controldevice 104 a, 104 b, 104 c, a daylight sensor 108 a, 108 b, 108 c, anoccupancy sensor 110 a, 110 b, 110 c, a motorized window treatment 112a, 112 b, 112 c, a shadow sensor 116 a, 116 b, 116 c, a thermostat 120a, 120 b, 120 c, and/or a plug-in load control device 122 a, 122 b, 122c.

Multiple load control devices can transmit wireless communications atthe same time and on the same channel, which tends to cause interferenceamong load control communications transmitted within the wireless range204. Some load control devices may transmit load control messages at thesame time because the load control messages may be transmitted based onthe detection of the same updated status event. For example, whendaylight sensors 108 a, 108 b, 108 c or shadow sensors 116 a, 116 b, 116c detect an increased level of light, each sensor may transmit a loadcontrol message. As each sensor may detect an increased level of lightat the same time, the load control messages transmitted by multiplesensors tends to be transmitted at the same time and cause interference.

As shown in FIGS. 2A and 2B, multiple load control devices may betransmitting load control communications within the same wireless range204. The wireless range 204 may include communications from load controldevices within one or more of the load control environments 102 a, 102b, 102 c, communications from other load control environments within thebuilding 202, and/or communications from load control devices in otherbuildings, such as the building 208 shown in FIG. 2B for example. As thenumber of wireless communications within the wireless range 204increases, the interference may also increase causing the number ofsuccessful communications to decrease.

Referring again to FIG. 2A, some load control systems use the systemcontroller 206 to coordinate the timing of the transmission of loadcontrol messages to avoid interference. The system controller 206 maydetect interference among load control messages transmitted within thewireless range 204 and may instruct some load control devices to delaycommunications to avoid message collision. While two-way communicationdevices may be capable of receiving transmission delay instructions fromthe system controller 206, one-way communication devices may be unableto receive the transmission delay instructions. The transmission ofthese transmission delay instructions within the wireless range 204 mayalso add to the number of communications being transmitted within thewireless range 204, which may cause additional interference initially.

Some control-source devices may independently determine the timing ofthe transmission of load control messages to avoid interference. Acontrol-source device may detect other communications that maypotentially cause interference. The control-source device may transmitload control messages when the amount of other communications within thewireless range 204 is below a threshold.

Some control-target devices may use the signal strength of received loadcontrol messages to filter out interference from load control messagesintended for a control-target device. A control-target device mayprocess load control messages that are received with a stronger signalstrength over load control messages received with a weaker signalstrength. For example, the motorized window treatment 112 a may receivea load control message from shadow sensor 116 b and may determine thereceived signal strength of the load control message. While receivingthe load control message from the shadow sensor 116 b, the motorizedwindow treatment 112 a may receive a load control message from theshadow sensor 116 a. The signal strength of the load control messagefrom the shadow sensor 116 a may be stronger because the shadow sensor116 a may be closer to the motorized window treatment 112 a. As a resultof the proximity of the shadow sensor 116 a to the motorized windowtreatment 112 a, the motorized window treatment 112 a will stopreceiving the load control message from the shadow sensor 116 b andbegin receiving and processing the load control message from the shadowsensor 116 a.

Filtering load control messages based on received signal strength mayallow a control-target device to filter out interfering messages andreceive the load control messages intended for the control-targetdevice. However, the load control messages intended for thecontrol-target device may reach a targeted device with a weaker signalstrength than an interfering signal, which may cause the load controlmessages intended for the control target device to be improperlydiscarded.

SUMMARY

A load control system may include control devices that may communicateload control messages to load control devices for controlling an amountof power provided to one or more electrical loads. The control devicemay be a load control device itself. As described herein, multiplecontrol devices may communicate load control messages at the same time,while mitigating the chance of interference. To prevent collision of theload control messages, the load control messages may be transmittedusing multiple wireless communication channels.

Each wireless communication channel may be assigned to a group ofcontrol devices that may be configured to communicate with one or moreload control devices within the group. The load control groups may becreated to isolate control devices that are intended to communicate withload control devices. The control devices and/or load control devices ineach load control group may be in the same physical area, such as a roomin a building, a floor in a building, a portion of a room or floor in abuilding, a number of adjacent rooms or floors in one or more buildings,or the like. If a communication channel is assigned to multiple loadcontrol groups, the groups that are on the same channel may be separatedby a pre-defined distance and/or by other groups that are configured tocommunicate on other channels, to avoid interference on the channelassigned to the groups.

Communications between devices may be performed via one or more groupcontrollers. Each group controller device may communicate with a groupof devices on a single channel. A group controller may communicate withmultiple groups of devices by transmitting and/or receiving on multiplechannels. The group controller may configure devices in a load controlgroup to communicate on the communication channel assigned to the loadcontrol group.

A control device and/or a load control device may be assigned to a loadcontrol group and/or configured communicate on a channel assigned to theload control group at the time of manufacture or at the time ofinstallation. The communication channel on which the devices in a loadcontrol group may communicate may be configured by pressing a button onthe device, pressing a combination of buttons on the device, or via thegroup controller device.

Control devices may send each load control message within a transmissionframe, which may be transmitted over a period of time allocated fortransmitting the load control message. The load control message may besent multiple times within the transmission frame to increase thelikelihood that the message may be successfully received. After a firsttransmission of the load control message, duplicate load controlmessages may be repeated within the transmission frame. The transmissionframe may be divided into equal sub-frames. A load control message maybe sent at a random time within each sub-frame. The load control messagemay be randomly transmitted within each sub-frame to increase thelikelihood of successful transmission and reduce the risk of collisions.The transmission frame may be followed by another transmission framethat may include a load control message within each sub-frame.

Control devices may transmit load control messages upon the detection ofa status event. The status event may indicate a status at a load controlenvironment (e.g., an amount of light or an occupancy) or a status of acontrol device (e.g., a button press). The status event may be detectedduring, or at the end of, a sampling time interval. While the samplingtime interval may be the same length for multiple control devicescommunicating within the load control system, the start and end of thesampling time interval may be offset between devices. After a statusevent is detected at a control device, the control device may transmit aload control message at a random time within a transmission timeinterval.

The transmission time interval may overlap with one or more othersampling time intervals for detecting another status event. If anotherupdated status event is detected before the random transmission of theload control message, the control device may determine whether to modifythe load control message or prevent the transmission of the load controlmessage (e.g., where the updated status that was detected is the same asthe current status being used to control the amount of power provided toan electrical load). If the load control message is modified, it may betransmitted at a random time within the transmission time interval. Therandom time at which the load control message is transmitted may be thesame as, or different from, the random time at which the load controlmessage was scheduled to be transmitted before the detection of theupdated status event. If the transmission of the load control message isprevented in the current transmission time interval, another loadcontrol message, or the modified load control message, that is based onthe updated status may be transmitted in the next transmission timeinterval. The next load control message may be transmitted during thenext uninterrupted transmission time interval.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an example prior art environment for controllingelectrical loads.

FIG. 2A depicts an example prior art environment in which interferencecan be caused by multiple communications transmitted for controllingelectrical loads.

FIG. 2B depicts another example prior art environment in whichinterference can be caused by multiple communications transmitted forcontrolling electrical loads.

FIG. 3A is a diagram depicting an example environment for controllingelectrical loads using channelization.

FIG. 3B is a diagram depicting another example environment forcontrolling electrical loads using channelization.

FIG. 4 is a simplified flow diagram illustrating an example method forperforming channelization.

FIGS. 5A and 5B are diagrams depicting example prior art configurationsfor transmitting load control messages.

FIG. 6 is a diagram depicting an example configuration for transmittingload control messages.

FIG. 7 is a simplified flow diagram illustrating an example method fortransmitting load control messages.

FIGS. 8A and 8B are diagrams depicting example configurations fordetecting status events and transmitting load control messages over adetection and reporting period.

FIG. 9A is a simplified flow diagram illustrating an example method fordetecting a status event and transmitting a load control message basedon the status event.

FIG. 9B is a simplified flow diagram illustrating an example method fordetecting a status event and determining whether to transmit a loadcontrol message based on detection of another status event.

FIG. 9C is a simplified flow diagram illustrating another example methodfor detecting a status event and determining whether to transmit a loadcontrol message based on detection of another status event.

FIG. 10 a block diagram depicting an example load control device.

FIG. 11 a block diagram depicting an example control device.

DETAILED DESCRIPTION

FIG. 3A is a diagram depicting an example environment for controllingelectrical loads using channelization. As shown in FIG. 3A, load controlenvironments 302 a, 302 b, 302 c may include control devices that maycommunicate load control messages for controlling an electrical load ata load control device. Each load control environment 302 a, 302 b, 302 cmay include one or more wireless control devices, such as a daylightsensor 308 a, 308 b, 308 c, an occupancy sensor 310 a, 310 b, 310 c, ashadow sensor 316 a, 316 b, 316 c, and/or a remote control device 318 a,318 b, 318 c. The load control environments 302 a, 302 b, 302 c mayinclude one or more load control devices, such as a lighting controldevice 304 a, 304 b, 304 c, a motorized window treatment 312 a, 312 b,312 c, a thermostat 320 a, 320 b, 320 c, and/or a plug-in load controldevice 322 a, 322 b, 322 c. The load control devices may controlcorresponding electrical loads in response to load control messagesreceived from the wireless control devices. For example, the wirelesscontrol devices may communicate with the load control devices bytransmitting wireless signals, e.g., radio-frequency (RF) signals,including the load control messages.

The load control messages may be sent from a control device to a loadcontrol device for indirectly controlling an electrical load. The loadcontrol device may directly control the electrical load based on theload control message received from the control device. The controldevice may be referred to as a control-source device, as the controldevice may be the source of the load control message. The load controldevice may be referred to as a control-target device, as the loadcontrol device may be the target of the load control message. Thecontrol-target devices may be capable of receiving and/or implementingcontrol instructions based on load control messages received from one ormore control-source devices. A control device may be both acontrol-target and a control-source device. A control device may be aload control device itself or any other device capable of communicatingload control messages for controlling a load control device.

The load control environments 302 a, 302 b, 302 c may be included in abuilding 324. The building 324 may be a commercial building, aresidence, or other structure. Load control environments 302 a, 302 b,and 302 c may be on the same floor in the building 324. The building 324may include one or more other floors that may include other load controlenvironments having one or more control devices and/or one or more loadcontrol devices.

Each control device and/or load control device may be included in a loadcontrol group that may be used to communicate load control messages onthe same communication channel or channels (e.g., using the samecommunication frequency or frequencies). A group configuration mayinclude control devices and/or load control devices within the same loadcontrol environment or set of load control environments, such as loadcontrol environments 302 a, 302 b, 302 c. The control devices and/orload control devices in a load control group may be on the same floor,in a group of consecutive floors, on different floors, or in anotherconfiguration within a wireless communication range 340 of a groupcontroller 342 (e.g., a system controller or central controller).

Load control groups may be configured based on control device type,where each load control group may include one or more control devices ofthe same device type. For example, the occupancy sensors 310 a, 310 b,310 c may be included in a load control group, while the daylightsensors 308 a, 308 b, 308 c may be included in another load controlgroup. In another example, daylight sensors 308 a, 308 b, 308 c andoccupancy sensors 310 a, 310 b, 310 c may be included in a group ofsensing devices, along with shadow sensors 316 a, 316 b, 316 c. Controldevices capable of one-way communication within a defined area may alsobe included in a load control group. If different control devices areincluded in different load control groups, the control-target devices towhich load control messages may be directed may communicate on multiplechannels to receive load control messages. Load control groups may beconfigured based on load control device type, where each load controlgroup may include one or more control devices capable of communicatingwith the same load control device type.

The control devices in load control environments 302 a, 302 b, 302 c maybe included in a load control group 326. The building 324 may includeother load control groups 328, 330, 332, 334, 336, 338. Each of theother load control groups 328, 330, 332, 334, 336, 338 may include othercontrol devices that may transmit load control messages to load controldevices. The other load control groups 328, 330, 332, 334, 336, 338 maybe on different floors in the building 324 from the load control group326. Each of the load control groups 328, 330, 332, 336, 338 may beassigned a different communication channel than the load control group326 for communicating load control messages.

Some load control groups may be assigned the same communication channel.For example, the load control group 334 may be assigned the samecommunication channel as the load control group 326. When more than oneload control group is assigned the same channel, the groups may beseparated to avoid interference between communications. As load controlgroups 326 and 334 may be assigned the same communication channel, theload control group 326 and the load control group 334 may be separatedby one or more other groups, such as load control groups 328, 330 and332, which may communicate on different wireless communication channelsthan load control groups 326 and 334. The load control groups 326, 328,330 and 332 may communicate on consecutive channels, or channels havingthe same distance apart, within a wireless frequency band. The distancebetween each channel in the frequency band may be determined by dividingthe wireless frequency band by the number of groups that may communicateon a different channel.

The distance between load control groups 326 and 334 may be a predefineddistance configured based on the configuration of the load controlsystem. In one example, the load control groups that are assigned thesame communication channel may be separated by a number of floors (e.g.,5 floors) in the building 324. The distance between the load controlgroups may cause attenuation to load control messages beingcommunicated. The distance between each floor may be between about 12feet and about 14 feet. The building 324 may include steel, concrete, orother materials that may cause additional attenuation (e.g., 6 dB ofattenuation) of the RF signals as the RF signals pass through each floorof the building.

As illustrated in FIG. 3A, the load control channels of the load controlgroups 326, 328, 330, 332, 334, 336, 338 may be assigned in a pattern.Groups 326, 328, 330, and 332 may be assigned different communicationchannels. Group 334 may begin the next iteration of the channel patternassigned to groups 326, 328, 330, and 332. Group 334 may be assigned thesame channel as group 326; group 336 may be assigned the same channel asgroup 328; and group 338 may be assigned the same channel as group 330.The groups may be assigned the same communication channel in a patternto create a pre-determined amount of distance between different groupsthat may communicate on the same channel. While FIG. 3A shows loadcontrol groups that are assigned the same channel being separated by anumber of floors in the building 324, the load control groups that areassigned the same channel may be separated by other load control groupson the same floor or any other distance to mitigate interference betweenload control messages transmitted between devices in different loadcontrol groups.

Control devices and/or load control devices may be assigned to the loadcontrol groups 326, 328, 330, 332, 334, 336, 338 at the time ofmanufacture or at the building 324 in which the load control devices maybe installed. The devices within each load control group 326, 328, 330,332, 334, 336, 338 may be configured to communicate on the assignedcommunication channel using a button press, a sequence of buttonpresses, or a remote communication from a configuration device. If adevice is assigned to a group at manufacture, the communication channelof the assigned group may be hard-coded during manufacture. The loadcontrol groups 326, 328, 330, 332, 334, 336, and 338 may be assignedcommunication channels based on the number of wireless communicationchannels available to the load control system. An example load controlsystem may include sixteen channels that may be used for channelization.

The devices in load control groups 326, 328, 330, 332, 334, 336, and 338may communicate load control messages directly or via the groupcontroller 342. The communications between the devices in a load controlgroup may be wireless or wired communications. The communicationsbetween the devices and the group controller 342 may be wireless orwired communications. The load control messages may include load controlinstructions or an indication of a status event from which load controlinstructions may be determined. The status event may indicate a statusat a load control environment (e.g., an amount of light or an occupancyat the load control environment) or a status of a control device (e.g.,a button press at the control device). The status event may include auser identified command, a measured light level in a load controlenvironment, a detected movement or lack of movement within the a loadcontrol environment (e.g., an occupancy or vacancy condition), an amountof light directly received from outside of a load control environment,or another status event that may be used to control an electrical load.The group controller 342 may receive the indication of the status eventand may determine load control instructions for being sent to one ormore load control devices.

The group controller 342 may correspond to the devices of the loadcontrol group 326 or may communicate with load control devices of one ormore of the other load control groups 328, 330, 332, 334, 336, 338. Ifthe group controller 342 is dedicated to the load control group 326, thegroup controller 342 may communicate on the channel assigned to the loadcontrol group 326, while one or more other group controllers maycommunicate on the channel assigned to each of the other groups 328,330, 332, 334, 336, 338. The group controllers may communicate with oneanother via a wired (e.g., Ethernet) or wireless communication link tosend and/or receive information. If the group controller 342communicates on the channel assigned to the load control group 326, itmay also communicate on the channel assigned to the load control group334. If the group controller 342 is not dedicated to the load controlgroup 326, the group controller 342 may communicate on the channelassigned to one or more other load control groups 328, 330, 332, 336,338 that may be in the wireless range 340 of the group controller 342.

The group controller 342 may configure the control devices and/or theload control devices to communicate on an assigned channel. The groupcontroller 342 may send instructions to a device that indicate thechannel on which the device may transmit and/or receive load controlmessages. The group controller 342 may send a broadcast message of thegroup assignments for the load control system and the control devicesand/or the load control devices may individually determine theirassigned load control groups and/or communication channel. In anotherexample, the group controller 342 may send each device its groupassignment and/or assigned communication channel.

FIG. 3B is a diagram depicting another example environment forcontrolling electrical loads using channelization. As shown in FIG. 3B,the wireless range 340 of the group controller 342 within which thedevices in the building 324 and/or the group controller 342 maycommunicate load control messages may also include devices in anotherbuilding 344. The building 344 may include load control groups 346, 348,350, 352, 354, 356, 358. The load control groups 346, 348, 350, 352,354, 356, 358 may be on different floors in the building 344. While FIG.3B shows the load control groups 346, 348, 350, 352, 354, 356, 358occupying different floors in the building 344, each load control group346, 348, 350, 352, 354, 356, 358 may occupy multiple floors, a portionof a floor, or another space in which load control communications may betransmitted or received.

The load control groups 346, 348, 350, 352, 354, 356, 358 in thebuilding 344 may communicate on the same wireless communication channelsas the load control groups 326, 328, 330, 332, 334, 336, 338 in thebuilding 324. The load control groups 346, 348, 350, 352, 354, 356, 358in the building 344 may be staggered differently than the load controlgroups 326, 328, 330, 332, 334, 336, 338 in the building 324 to avoidinterference. As shown in FIG. 3B, the load control groups 346 and 348may communicate load control messages on different communicationchannels than the other load control groups 326 and 328 that are in thewireless range 340.

The load control groups 326, 328, 330, 332, 334, 336, 338 and the loadcontrol groups 346, 348, 350, 352, 354, 356, 358 may be configured suchthat the load control groups that are assigned the same communicationchannel are not in the same wireless range. The communication channelsto which the load control groups 346, 348, 350, 352, 354, 356, 358 areassigned may be in the same pattern as the communication channels towhich the load control groups 326, 328, 330, 332, 334, 336, 338 areassigned. The load control groups may be staggered differently inbuilding 344, such that the communication channels assigned to loadcontrol groups 346, 348, 350, 352, 354, 356, 358 are offset from thecommunication channels assigned to load control groups 326, 328, 330,332, 334, 336, 338. This staggering may create a distance betweendifferent load control groups that are assigned the same communicationchannel.

The load control groups 346, 348, 350, 352, 354, 356, 358 in thebuilding 344 may be staggered such that each load control group in thebuilding 344 is at least a predefined distance from a load control groupin the building 324 that communicates on the same wireless communicationchannel. For example, the load control groups in buildings 324 and 344may be staggered by three to five floors to avoid interference betweendevices in different groups communicating on the same channel. The groupconfiguration in the buildings 324 and 344 may depend on the distance360 between the buildings. As the distance 360 increases, the number offloors between each load control group communicating on the same channelmay decrease. As the distance 360 decreases, the distance (e.g., numberof floors) between each load control group communicating on the samechannel may increase. Due to the distance 360, the number of floorsbetween the load control groups in the building 324 and the building 344that communicate on the same channel (e.g., load control group 326 andload control group 350, respectively) may be less than the number offloors between load control groups in the same building 324 thatcommunicate on the same channel (e.g., load control group 326 and loadcontrol group 334).

FIG. 4 is a simplified flow diagram illustrating an example method 400for performing channelization. The method 400 may be performed by one ormore group controllers (e.g., the group controller 342) or other devicesthat may communicate with one or more load control groups bycommunicating on multiple wireless communication channels. The method400 may begin at 402. At 404, a load control message may be receivedfrom a control device in a first load control group. The load controlmessage received at 404 may be received on a wireless communicationchannel assigned to the first load control group.

Load control instructions may be determined at 406 based on the loadcontrol message received at 404. The load control instructions may bedetermined based on a status event received in the load control message.The status event may indicate a status at a load control environment(e.g., an amount of light or an occupancy status) or a status of acontrol device (e.g., a button press). The status event may include auser identified command, a measured light level in a load controlenvironment, a detected movement or lack of movement within a loadcontrol environment, an amount of light directly received from outsideof a load control environment, or another status event that may be usedto control an electrical load. The load control instructions may betransmitted to a load control device in the first load control group at408. The load control instructions transmitted at 408 may be transmittedon the wireless communication channel assigned to the first load controlgroup. At 410, the group controller may switch from the wirelesscommunication channel assigned to the first load control group to awireless communication channel assigned to a second load control group.

At 412, another load control message may be received on the wirelesscommunication channel assigned to the second load control group. Thewireless communication channel assigned to the second load control groupmay be different than the wireless communication channel assigned to thefirst load control group. The group controller may be switched from thewireless communication channel assigned to the first load control groupto the wireless communication channel assigned to the second loadcontrol group before receiving the load control message at 412. Inanother example, the group controller may be capable of communicating onboth channels simultaneously (e.g., dual communication via multipleantennas).

Load control instructions may be determined at 414 based on the loadcontrol message received at 412. The load control instructions may bedetermined based on a status event received in the load control message.The load control instructions may be transmitted to a load controldevice in the second load control group at 416. The load controlinstructions transmitted at 416 may be transmitted on the wirelesscommunication channel assigned to the second load control group. Themethod 400 may end at 418.

FIG. 5A is a diagram depicting an example prior art configuration fortransmitting load control messages from an occupancy sensor (e.g., oneof occupancy sensors 310 a, 310 b, 310 c). An occupancy sensor maydetect whether a load control environment is occupied or unoccupied andmay send an updated status event. The updated status event may be usedfor controlling an electrical load when an occupancy status of the loadcontrol environment changes (e.g., from unoccupied to occupied).

The status event may be detected over a fifteen second sampling period.Upon expiration of the fifteen second sampling period, the occupancysensor may detect an updated status event. When the updated status eventis detected, twelve updated status event messages 504, 506, 508, 510,512, 514, 516, 518, 520, 522, 524, 526 are transmitted within atransmission frame 502. The twelve updated status event messages 504,506, 508, 510, 512, 514, 516, 518, 520, 522, 524, 526 are duplicatemessages transmitted to increase the chance of at least one of thestatus event messages being properly received in case of interference.The updated status event messages 506, 508, 510, 512, 514, 516, 518,520, 522, 524, 526 may be duplicates of a first updated status eventmessage 504 that may be transmitted at the end of the previous samplingperiod.

The transmission frame 502 includes twelve sub-frames of equal lengththat are transmitted over a five second period of time allotted fortransmitting the updated status events 504, 506, 508, 510, 512, 514,516, 518, 520, 522, 524, 526. Each sub-frame lasts for a period ofapproximately 416 milliseconds. Each sub-frame includes thirty-two slotswithin which an updated status event can be transmitted. Each updatedstatus event 504, 506, 508, 510, 512, 514, 516, 518, 520, 522, 524, 526occurs in a respective sub-frame of the twelve sub-frames and istransmitted at a random slot within its respective sub-frame.

FIG. 5B is a diagram depicting an example prior art configuration fortransmitting load control messages from a daylight sensor or a shadowsensor. A daylight sensor may measure an amount of light within a loadcontrol environment and may send an updated status event for controllingan electrical load when the level of the light within a load controlenvironment changes, for example, by a predetermined amount. A shadowsensor may measure an amount of light received from outside of a loadcontrol environment and may send an updated status event for controllingan electrical load when the level of the light received from outside aload control environment changes, for example, by a predeterminedamount.

The status event may be detected over a fifteen second sampling period.Upon expiration of the fifteen second sampling period, the daylightsensor or the shadow sensor may detect an updated status event. When anupdated status event is detected, four updated status event messages530, 532, 534, 536 are transmitted within a transmission frame 528. Thefour updated status event messages 530, 532, 534, 536 may be duplicatemessages that are transmitted to increase the chance of at least one ofthe status event messages 530, 532, 534, 536 being properly received incase of interference. The updated status event messages 532, 534, 536may be duplicates of a first updated status event message 530 that maybe transmitted at the end of the previous sampling period.

The transmission frame 528 includes twelve sub-frames of equal lengththat are transmitted over a five second period of time allotted fortransmitting the updated status events 530, 532, 534, 536. Eachsub-frame lasts for over a period of approximately 416 milliseconds.Each sub-frame includes 32 slots within which an updated status eventcan be transmitted. The updated status events 530, 532, 534, 536 aretransmitted within the first four sub-frames of the twelve sub-framesthat make up the transmission frame 502. Each updated status event 530,532, 534, 536 occurs in a respective sub-frame of the first foursub-frames and is transmitted at a random slot within its respectivesub-frame. The four updated status events 530, 532, 534, 536 aretransmitted over a period of approximately 1.66 seconds, while the othereight sub-frames (extending for about the next 3.33 seconds) go unused.

As the updated status events are transmitted based on a detected event(e.g., an occupancy condition or a measured light level), multipledevices tend to detect the same updated status and transmit an updatedstatus event at the same time. As the number of devices detecting thesame updated status in an area increases, the chance of messagecollisions increases. When other load control messages are also beingtransmitted from other devices on the same channel and within the samearea, the chance of message collisions is even greater.

FIG. 6 is a diagram depicting an example configuration for transmittingload control messages 604, 606, 608, 610. The load control messages 604,606, 608, 610 may be transmitted by control devices, such as anoccupancy sensor, a daylight sensor, a shadow sensor, a remote controldevice, or any other control device for controlling an electrical load.The load control messages 604, 606, 608, 610 may include a status eventor other information for controlling a load control device. The statusevent may indicate a status at a load control environment (e.g., anamount of light or an occupancy condition) or a status of a controldevice (e.g., a button press). The status event may include a useridentified command, a measured light level in a load controlenvironment, a detected movement or lack of movement within a loadcontrol environment, an amount of light directly received from outsideof the load control environment, or another status event that may beused to control an electrical load.

The load control messages 604, 606, 608, 610 may be transmitted within atransmission frame 602. The transmission frame 602 may include foursub-frames of equal length that may be transmitted over a transmissiontime period allotted for transmitting the load control messages 604,606, 608, 610. The transmission time period may include a five secondperiod of time. Each sub-frame may be transmitted over a period ofapproximately 1.25 seconds. Each sub-frame includes 128 slots withinwhich a load control message may be transmitted. The updated loadcontrol messages 604, 606, 608, 610 may be transmitted at a random slotwithin a respective sub-frame within the transmission frame 602. Each ofthe four sub-frames of the transmission frame 602 may include arespective load control message 604, 606, 608, 610. The transmissionframe 602 may be followed by one or more other transmission frames thatare configured in a similar manner to transmission frame 602.

The load control messages 604, 606, 608, 610 may be transmitted randomlywithin the four 128-slot sub-frames within the transmission frame 602 tomitigate collisions between load control messages. The transmission offour load control messages 604, 606, 608, 610 may decrease the chance ofcollisions that may occur when more messages are transmitted. The128-slot sub-frame may allow for a lower chance of collision with othermessages that may be transmitted randomly within the same sub-frame.

FIG. 7 is a simplified flow diagram illustrating an example method 700for transmitting load control messages. The method 700 may be performedby a control device or another device that may communicate load controlmessages within a load control system. The method 700 may begin at 702.At 704, a transmission frame may be established for sending load controlmessages from a control device. The transmission frame may have a lengththat may be configured in a control device at manufacture, or that maybe received by a control device after manufacture (e.g., afterinstallation at a site). The transmission frame may be determined at 704to be communicated over a five second period of time.

The transmission frame may be divided into four equal sub-frames at 706.Each sub-frame may include 128 slots for transmitting a load controlmessage. At 708, the load control message may be transmitted at a randomslot once within each sub-frame of the transmission frame. Thetransmission frame transmitted at 708 may be followed by anothertransmission frame of four equally-sized sub-frames that each include arespective load control message (not shown). If another transmissionframe is sent after the transmission frame sent at 708, the controldevice may return to any of the steps 704, 706, or 708 to beginprocessing the subsequent frame. The method 700 may end at 710.

FIGS. 8A and 8B are diagrams that depict example configurations fordetecting status events and transmitting load control messages over adetection and reporting period 802. The detection and reporting period802 may include a sampling time interval 804 within which a status event808 may be detected at a control device. The control device may includean occupancy sensor, a daylight sensor, a shadow sensor, a remotecontrol device, or other control device capable of detecting the statusevent. The detection and reporting period 802 may include a transmissiontime interval 806 within which a load control message 810 may betransmitted. The load control message 810 may be a load control message(e.g., a first load control message) in a transmission frame, such asthe transmission frame 602 for example, that includes duplicate loadcontrol messages. The load control message 810 may include the statusevent 808 and/or load control information determined based on the statusevent 808. The status event 808 may include a user identified command, adetected level of available daylight in a load control environment, adetected movement or lack of movement within a load control environment,an amount of light directly received from outside of a load controlenvironment, or another status event that may be used to control anelectrical load. The information based on the status event 808 mayinclude load control instructions for turning a lighting load on/off,load control instructions for increasing/decreasing a dimming level of alighting load, load control instructions for increasing/decreasing aposition of a window covering material, load control instructions forincreasing/decreasing a temperature of an HVAC system, and/or the like.

As shown in FIG. 8A, the length of the transmission time interval 806may be larger than the length of the sampling time interval 804. Thetransmission time interval 806 may be a multiple of the sampling timeinterval 804. For example, the sampling time interval 804 may be afifteen-second time interval for detecting the status event 808 and thetransmission time interval 806 may be a thirty-second time interval fortransmitting the load control message 810. Upon detection of the statusevent 808, or at the end of the sampling time interval 804, the statusevent 808, or information determined from the status event 808, may beincluded in the load control message 810. The load control message maybe transmitted at a random time within the transmission time interval806.

As shown in FIG. 8B, the transmission time interval 806 may overlap withone or more other sampling time intervals, such as sampling timeintervals 812, 814. The sampling time intervals 812, 814 may follow thesampling time interval 804 and may be used for detecting additionalstatus events. In the sampling time interval 812, the control device maydetect a status event 816. The status event 816 may be detected beforethe load control message 810 is transmitted. If the status event 816 isdetected, and/or the sampling time interval 812 expires, before the loadcontrol message 810 is randomly transmitted within the transmission timeinterval 806, the control device may determine whether the status event816 is an updated status event from the status event 808. The statusevent 816 may be an updated status event if it indicates differentstatus information than the status event 808.

The load control message 810 may be modified and/or the transmission ofthe load control message 810 may be changed or prevented based on thedetection of the status event 816. If the status event 816 is not anupdated status event, the control device may send the load controlmessage 810 unaltered. If the status event 816 is an updated statusevent, the control device may alter the load control message 810 basedon the updated status event 816 or cancel the transmission of the loadcontrol message 810 within the transmission time interval 806. Thealtered load control message 810 may still be randomly transmittedwithin the transmission time interval 806 or transmission may be delayeduntil the next transmission time interval. If the updated status event816 indicates a status that existed before the status event 808 wasdetected, the transmission of the load control message 810, or any otherload control message associated with the status event 808, may beprevented altogether. This may allow a reduction in the overallbandwidth being used, as multiple status events 808 and 816 may becommunicated with a single load control message 810, or the transmissionof the load control message 810 may be prevented by the detection of anupdated status event 816 that may indicate the same status that existedprior to detection of the status event 808 (e.g., an interim short-livedstatus event).

The sampling time interval 804 and/or the transmission time interval 806may be offset across multiple devices, such that communications based ondetected status events may avoid collisions. The sampling time interval804 and/or the transmission time interval 806 may be offset by adifferent timing at an internal clock on which the sampling timeinterval 804 and/or the transmission time interval 806 may be based. Theinternal clocks on each device may drift at different rates and may moveapart from one another over time, and/or may be set at different times.

FIG. 9A is a simplified flow diagram illustrating an example method 900for detecting a status event and transmitting a load control messagebased on the status event. The method 900 may be performed by a controldevice or another device in a load control system capable of detecting astatus event. The method 900 may begin at 902. At 904, a status eventmay be detected during or after a sampling time interval. The statusevent may indicate a status at a load control environment (e.g., anamount of light or an occupancy condition) or a status of a controldevice (e.g., a button press). The sampling time interval may be afifteen-second time interval.

A load control message may be created at 906 based on the status eventdetected at 904. The load control message may include updated statusinformation or may indicate that the status of the load controlenvironment is unchanged. The load control message created at 906 may betransmitted at a random time within a transmission time interval at 908.The load control message may be a first load control message in atransmission frame, such as transmission frame 602 for example, thatincludes duplicate load control messages. The transmission time intervalmay follow the sampling time interval. The transmission time intervalmay be a multiple of the sampling time interval. For example, if thelength of the sampling time interval is fifteen seconds, thetransmission time interval may be a thirty-second time interval. Theload control message may be transmitted at a random time within thetransmission time interval to avoid interference with other load controlmessages within the load control system. For example, other controldevices in the load control system may be transmitting load controlmessages based on the same status event detected at 904. The method 900may end at 910.

FIG. 9B is a simplified flow diagram illustrating an example method 912for detecting a status event and determining whether to transmit a loadcontrol message based on detection of another status event. The method912 may be performed by a control device or another device in a loadcontrol system capable of detecting a status event. The method 912 maybegin at 914. At 916, a status event may be detected during or after asampling time interval. A load control message may be created at 918based on the status event detected at 916. The load control message mayinclude updated status information or may indicate that the status ofthe load control environment is unchanged.

A control device may determine whether an updated status event has beendetected at 920. For example, the next sampling time interval mayoverlap with the transmission time interval for transmitting the loadcontrol message based on the detected status event. The transmissiontime interval may include multiple sampling time intervals. If anupdated status event is detected at 920, the method 912 may return to918 and may modify the load control message or create a different loadcontrol message based on the detected updated status event. Transmissionof the load control message based on the updated status event may bedelayed until the next transmission time interval or may be transmittedwithin the same transmission time interval in which it is detected. Ifan updated status event is not detected at 920, or another updatedstatus event is not detected after modification of the control messageat 918, the load control message may be transmitted at a random timewithin the transmission time interval at 922. The method 912 may end at924.

FIG. 9C is a simplified flow diagram illustrating an example method 926for detecting a status event and determining whether to transmit a loadcontrol message based on detection of a subsequent status event. Themethod 926 may be performed by a control device or another device in aload control system capable of detecting a status event. The method 926may begin at 928. At 930, a status event may be detected during or aftera sampling time interval. A load control message may be created at 932based on the status event detected at 930.

A control device may determine whether an updated status event has beendetected at 934. For example, the determination at 934 may be madebefore transmission of the load control message. If the updated statusevent is not detected at 934 before the transmission of the load controlmessage, the load control message may be randomly transmitted within thetransmission time interval at 936. If an updated status event isdetected at 934, the transmission of the load control message may beprevented at 938. For example, the updated status event detected at 934may be compared with a status event prior to the status event detectedat 930 and if the updated status event detected at 934 indicates thesame status that existed prior to the status event detected at 930, thetransmission of the load control message may be prevented at 938. Thetransmission of the load control message may be prevented at 938 becausethe load control message based on the updated status event detected at934 may include similar information or instructions that are currentlybeing used to control an electrical load. In another example, thetransmission of the load control message may be prevented at 938 infavor of being transmitted in a later transmission time interval. Themethod 926 may end at 940. While FIGS. 9B and 9C illustrate the creationof the load control message at 918 and 932, respectively, beforedetermining whether an updated status event has been detected, the loadcontrol message may be created after an updated status event has beendetected. For example, the load control message may be created at 918and 932 after it is determined at that a load control message should betransmitted at 922 and 936, respectively.

FIG. 10 is a block diagram depicting an example load control device1000. The load control device 1000 may be a dimmer switch, an electronicswitch, an electronic ballast for lamps, an LED driver for LED lightsources, a plug-in load control device, a temperature control device(e.g., a thermostat), a motor drive unit for a motorized windowtreatment, or other load control device capable of directly controllingan electrical load. The load control device 1000 may include acommunication circuit 1002. The communication circuit may perform wiredand/or wireless communications with other devices. The communicationscircuit 1002 may include a radio-frequency (RF) receiver, an RFtransceiver, or other communications module capable of performingwireless communications via an antenna 1016. The communications circuit1002 may be in communication with control circuit 1004 for transmittingand/or receiving information.

The control circuit 1004 may include one or more general purposeprocessors, special purpose processors, conventional processors, digitalsignal processors (DSPs), microprocessors, integrated circuits, aprogrammable logic device (PLD), application specific integratedcircuits (ASICs), or the like. The control circuit 1004 may performsignal coding, data processing, power control, input/output processing,or any other functionality that enables the load control device 1000 toperform as described herein.

The control circuit 1004 may store information in and/or retrieveinformation from a memory 1006. The memory 1006 may maintain a registryof associated control devices and/or group controllers with which theload control device 1000 may communicate. The memory 1006 may maintain aregistry of load control groups and/or associated communication channelson which load control messages may be received. The memory 1006 mayinclude a non-removable memory and/or a removable memory.

The load control circuit 1008 may control the electrical load 1010 inresponse to the control circuit 1004. The load control circuit 1008 mayreceive power via the hot connection 1012 and the neutral connection1014 and may provide an amount of power to the electrical load 1010. Theelectrical load 1010 may include any type of electrical load.

FIG. 11 is a block diagram depicting an example wireless communicationdevice 1100. The wireless communication device 1100 may be a controldevice or a group controller device as described herein. The wirelesscommunication device 1100 may include a control circuit 1102 forcontrolling the functionality of the wireless communication device 1100.The control circuit 1102 may include one or more general purposeprocessors, special purpose processors, conventional processors, digitalsignal processors (DSPs), microprocessors, integrated circuits, aprogrammable logic device (PLD), application specific integratedcircuits (ASICs), or the like. The control circuit 1102 may performsignal coding, data processing, power control, input/output processing,or any other functionality that enables the wireless communicationdevice 1100 to perform as described herein.

The control circuit 1102 may store information in and/or retrieveinformation from the memory 1104. The memory 1104 may include anon-removable memory and/or a removable memory. The memory 1104 maymaintain a registry of associated load control devices and/or groupcontrollers with which the wireless communication device 1100 maycommunicate. The memory 1104 may maintain a registry of load controlgroups and/or associated communication channels on which load controlmessages may be transmitted. Transmission frame configurations, samplingtime intervals, and/or transmission time intervals may be maintained inthe memory 1104.

The wireless communication device 1100 may include a communicationscircuit 1106 for transmitting and/or receiving information. Thecommunications circuit 1106 may transmit and/or receive information viawired and/or wireless communications. The communications circuit 1106may include an RF transmitter, an RF transceiver, or other circuitcapable of performing communications via an antenna 1108. Thecommunications circuit 1106 may be in communication with control circuit1102 for transmitting and/or receiving information.

The control circuit 1102 may also be in communication with an inputcircuit 1110. The input circuit 1110 may include a button or a sensorcircuit (e.g., an occupancy sensor circuit, a daylight sensor circuit,or a temperature sensor circuit) for receiving input that may be sent toa device for controlling an electrical load. The control circuit 1102may receive information from the input circuit 1110 (e.g., an indicationthat a button has been actuated or sensed information). The controlcircuit 1102 may retrieve load control instructions from the memory 1104based on the information received from the input circuit 1110. Thecontrol circuit 1102 may send the information received from the inputcircuit 1110 to another device via the communications circuit 1106. Eachof the modules within the wireless communication device 1100 may bepowered by a power source 1112.

Although features and elements are described herein in a particularsequence or in combinations, each feature or element can be used aloneor in any combination with the other features and elements. The methodsdescribed herein may be implemented in a computer program, software, orfirmware incorporated in a computer-readable medium for execution by acomputer or processor. Examples of computer-readable media includeelectronic signals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), removable disks, and optical media such asCD-ROM disks, and digital versatile disks (DVDs).

What is claimed:
 1. A load control system configured to send loadcontrol messages from a plurality of control devices, and wherein eachload control message is transmitted for controlling an amount of powerprovided to an electrical load, the load control system comprising: afirst load control group that includes at least one control deviceconfigured to send load control messages on a first wirelesscommunication channel for controlling an electrical load; a second loadcontrol group that includes at least one control device that is a sametype of control device as the at least one control device of the firstload control group, and wherein the at least one control device of thesecond load control group is capable of causing interference with theload control message transmitted by the at least one control device ofthe first load control group by sending a respective load controlmessage on the first wireless communication channel, wherein the secondload control group is configured to transmit on a second wirelesscommunication channel to avoid the interference with the load controlmessages from the at least one control device in the first load controlgroup; and a third load control group configured to transmit loadcontrol messages on the first wireless communication channel, andwherein the first load control group and the third load control groupare separated by a plurality of other load control groups that areconfigured to communicate load control messages on a plurality of otherwireless communication channels to avoid interference between the loadcontrol messages of the first load control group and the load controlmessages of the third load control group.
 2. The load control system ofclaim 1, wherein the first load control group resides on a differentfloor in a building than the second load control group.
 3. The loadcontrol system of claim 1, wherein the first load control group resideson a different floor in a building than the third load control group,and wherein each of the plurality of other load control groups reside onconsecutive floors in the building between the floor on which the firstload control group resides and the floor on which the second loadcontrol group resides.
 4. The load control system of claim 3, whereineach floor includes a different load control group configured tocommunicate on a respective wireless communication channel.
 5. The loadcontrol system of claim 1, wherein the plurality of other wirelesscommunication channels includes consecutive channels within a wirelessfrequency band.
 6. The load control system of claim 1, wherein the firstload control group resides on a different floor and in a differentbuilding than the second load control group.
 7. The load control systemof claim 1, wherein the first load control group and the second loadcontrol group include control-source devices.
 8. The load control systemof claim 1, wherein the at least one control device of the first loadcontrol group and the at least one control device of the second loadcontrol group include one-way communication devices.
 9. A groupcontroller device for enabling communication of load control messagesbetween control devices and load control devices, wherein the controldevices are configured to send the load control messages to the loadcontrol devices to control an amount of power provided to an electricalload, and wherein the load control devices are configured to directlycontrol the amount of power provided to the electrical load based on theload control messages, the group controller device comprising: at leastone communication circuit configured to: receive, via a first wirelesscommunication channel, a first load control message from a controldevice in a first load control group, transmit, via the first wirelesscommunication channel, load control instructions to a load controldevice in the first load control group, receive, via a second wirelesscommunication channel, a second load control message from a controldevice in a second load control group, wherein the control device in thesecond load control group is a same type of control device as thecontrol device in the first load control group, wherein the second loadcontrol message from the control device in the second load control groupis capable of causing interference with the first load control messagefrom the control device in the first load control group if sent on thefirst wireless communication channel, and transmit, via the secondwireless communication channel, load control instructions to a loadcontrol device in the second load control group; and a control circuitconfigured to: determine the load control instructions for the loadcontrol device in the first load control group based on the first loadcontrol message received from the control device in the first loadcontrol group, and determine the load control instructions for the loadcontrol device in the second load control group based on the second loadcontrol message received from the control device in the second loadcontrol group.
 10. The group controller device of claim 9, wherein thefirst load control group resides on a different floor in a building thanthe second load control group.
 11. The group controller device of claim10, wherein the first load control group and the second load controlgroup are separated by a plurality of other load control groups, whereineach of the plurality of other load control groups reside on consecutivefloors between the floor on which the first load control group residesand the floor on which the second load control group resides.
 12. Thegroup controller device of claim 9, wherein the control device in thefirst load control group and the control device in the second loadcontrol group are one-way communication devices.
 13. A load controlsystem configured to coordinate load control messages between controldevices and load control devices, wherein the control devices areconfigured to send the load control messages to the load control devicesto control an amount of power provided to an electrical load, andwherein the load control devices are configured to directly control theamount of power provided to the electrical load based on the loadcontrol messages, the load control system comprising: a first groupcontroller for a first load control group configured to: receive, via afirst wireless communication channel, a first load control message froma control device in the first load control group, determine load controlinstructions for a load control device in the first load control groupbased on the first load control message received from the control devicein the first load control group, and transmit, via the first wirelesscommunication channel, the load control instructions to the load controldevice in the first load control group; and a second group controllerfor a second load control group configured to: receive, via a secondwireless communication channel, a second load control message from acontrol device in the second load control group, wherein the controldevice in the second load control group is a same type of control deviceas the control device in the first load control group, wherein thesecond load control message from the control device in the second loadcontrol group is capable of causing interference with the first loadcontrol message from the control device in the first load control groupif sent on the first wireless communication channel, determine loadcontrol instructions for a load control device in the second loadcontrol group based on the second load control message received from thecontrol device in the second load control group, and transmit, via thesecond wireless communication channel, the load control instructions tothe load control device in the second load control group.
 14. The loadcontrol system of claim 13, wherein the first load control group resideson a different floor in a building than the second load control group.15. The load control system of claim 13, wherein the first load controlgroup resides on a different floor and in a different building than thesecond load control group.
 16. The load control system of claim 15,wherein the first load control group and the second load control groupare separated by a plurality of other load control groups, wherein eachof the plurality of other load control groups reside on consecutivefloors between the floor on which the first load control group residesand the floor on which the second load control group resides.
 17. Theload control system of claim 13, wherein the control device in the firstload control group and the control device in the second load controlgroup are one-way communication devices.